OC leaders say the area near the tank is safe. Experts say the risks continue

After six days of trying to prevent an overheated chemical tank from exploding into a giant fireball or spilling thousands of gallons of toxic material at the Garden Grove airport, Orange County leaders announced Tuesday that the risk of a catastrophic explosion is largely over.

Local authorities lifted much of the evacuation zone around GKN Aerospace and allowed tens of thousands of residents to return.

Firefighters sprayed more than 9 million liters of water into the hot methyl methacrylate (MMA) tank, significantly lowering the vessel’s temperature – but not before the high temperatures caused severe pressure and a crack in the side of the tank, which acts as a relief valve.

Orange County Fire Authority interim chief TJ McGovern indicated at a public meeting Tuesday afternoon that evacuation zones may be significantly reduced. He mentioned that the crew has stopped pumping water into the tank and are in the process of checking if the ship’s temperature has stabilized.

“Once we know that the temperature is stable, we will be taking the risk of fire off the table,” he said. “If there is no fire hazard, our evacuation points will be reduced.”

McGovern said, at about 5 p.m., that officials are “hopeful that we will have a positive outcome very soon.” He asked the public to continue to be patient over the next few hours as crews worked to confirm the initial information they were seeing about temperature stability.

Orange County health and fire officials insisted there were no fumes or chemical leaks during the six-day crisis. The US Environmental Protection Agency said its air monitors around the facility did not detect methyl methacrylate or other toxic chemicals in the air (known as volatile organic compounds).

But environmentalists remain skeptical that no toxic substances have been released. Andrew Whelton, a Purdue University professor who studies natural disasters, said a broken chemical tank would be like a soda can with a hole punched in it.

“I find it hard to believe that you can heat a tank with [chemical] like methyl methacrylate, see that it clearly cracks under pressure and assume nothing came out of it,” Whelton said.

It’s possible, Whelton said, that spraying a large amount of water into the tank effectively suppressed the toxic vapors and airborne hazards.

Fire officials had earlier said that the MMA tank was experiencing a thermal runaway, a chain reaction that led to an uncontrollable rise in temperatures. They said the situation may have ended in an explosion or chemical spill.

Welton said an explosion is still possible.

To guard against a possible spill, authorities set up sandbag barriers to keep the chemical from storm drains leading to the sea.

The Orange County Fire Authority said it was also testing the water in the tank to make sure it didn’t have high levels of contaminants.

Jane Williams, executive director of California Communities Against Toxics, warned that MMA is just one of the chemicals being stored in the environment. He fears that there is danger from other chemicals.

The company in 2024 reported that, in addition to MMA, it emitted thousands of pounds of flammable chemicals, including methyl ethyl ketone and methanol n-butyl alcohol, according to records from the South Coast Air Quality Management District.

In the past, GKN Aerospace has been named for failing to disclose flammable chemicals at other facilities.

In 2007, the US EPA alleged that the company stored approximately 8,000 kilograms of hydrofluoric acid and 34,000 pounds of nitric acid at the Kent, Wash., facility – but neglected to report these quantities to the appropriate government agencies.

Last year, the company settled with the EPA over allegations that it improperly stored hazardous waste at a facility near San Diego.

“To me, this is not about MMA,” Williams said. “You have a company that has a lot of chemicals, it lost control, it is outside residential areas. I don’t trust this company to reveal what is on its site. I don’t trust the first responders. I don’t trust them with my life.